1. Field of the Invention
The invention relates to an ink jet printer which has plural ink jet recording heads moving in the width direction of a recording sheet and ejects ink of plural colors in accordance with printing data to print a color image, and also to an ink jet recording apparatus in which plural ink jet recording heads are mounted on the same carriage so as to realize high density printing. More particularly, the invention relates to a capping device which seals an ink jet recording head suitable for such a recording apparatus.
2. Related Art
An on-demand ink jet recording apparatus ejects ink pressurized in a pressurizing chamber from a nozzle as ink drops to a recording sheet, to record printing data on the sheet. Such an apparatus has a problem in that printing failures are caused by increased viscosity of the ink due to evaporation of ink solvent through nozzle openings, the drying of ink, adhesion of dust, introduction of air bubbles, etc. To alleviate this problem, an ink jet recording apparatus is provided with a capping device which seals nozzle openings during a nonprinting period.
Such a capping device is proposed in, for example, Unexamined Japanese Patent Publication No. Hei. 1-125239. In the proposed capping device, a slider is pushed by a carriage returning toward the home position, to be moved toward a nozzle face of a recording head along an inclined guide face which is formed on a frame, and a cap member disposed on the surface of the slider is made to press against and contact with the recording head, thereby sealing nozzles.
Since developments in personal computers allow graphic processing to be executed in a relatively simple manner, a printer which can output a hard copy of a color image displayed on a screen is requested. In view of differences in ink consumption and recording density between colors, and also the prevention of discoloration during a quiescent time, an ink jet printer which can perform such a color printing is so configured that two recording heads, i.e., a recording head for black and white printing and a recording head for color printing, are mounted on one carriage.
Consequently, a capping device must be disposed for each of plural ink jet recording heads, and driving mechanisms for respectively moving the capping devices so as to cover and uncover the recording heads are required. This produces a problem in that the whole structure of the printer is complicated.